Make base::PowerMonitor work on Chrome OS.

On Chrome OS, updates about the system power status are
received via D-Bus messages on the UI thread. Being in
base/, PowerMonitor can't depend on the code in chromeos/
that receives those messages, so make the Chrome OS code
instead notify PowerMonitor when it receives updates.

BUG=326534

Review URL: https://codereview.chromium.org/622693004

Cr-Commit-Position: refs/heads/master@{#298367}

5 files changed, 76 insertions, 2 deletions

diff --git a/base/BUILD.gn b/base/BUILD.gn
index 0a4f6a9..a190ea3 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -445,6 +445,7 @@ component("base") {
     "power_monitor/power_monitor_device_source.h",
     "power_monitor/power_monitor_device_source_android.cc",
     "power_monitor/power_monitor_device_source_android.h",
+    "power_monitor/power_monitor_device_source_chromeos.cc",
     "power_monitor/power_monitor_device_source_ios.mm",
     "power_monitor/power_monitor_device_source_mac.mm",
     "power_monitor/power_monitor_device_source_posix.cc",
@@ -802,6 +803,12 @@ component("base") {
     ]
   }
 
+  if (is_chromeos) {
+    sources -= [
+      "power_monitor/power_monitor_device_source_posix.cc",
+    ]
+  }
+
   if (is_nacl) {
     # These things would otherwise be built on a Posix build but aren't
     # supported on NaCl.
diff --git a/base/base.gypi b/base/base.gypi
index 8a37249..c5796ef 100644
--- a/base/base.gypi
+++ b/base/base.gypi
@@ -432,6 +432,7 @@
           'power_monitor/power_monitor.h',
           'power_monitor/power_monitor_device_source_android.cc',
           'power_monitor/power_monitor_device_source_android.h',
+          'power_monitor/power_monitor_device_source_chromeos.cc',
           'power_monitor/power_monitor_device_source.cc',
           'power_monitor/power_monitor_device_source.h',
           'power_monitor/power_monitor_device_source_ios.mm',
@@ -838,6 +839,11 @@
                'ANDROID_SINCOS_PROVIDED',
             ],
           }],
+          ['<(chromeos) == 1', {
+            'sources!': [
+              'power_monitor/power_monitor_device_source_posix.cc',
+            ],
+          }],
           ['OS == "ios" and _toolset != "host"', {
             'sources/': [
               # Pull in specific Mac files for iOS (which have been filtered out
diff --git a/base/power_monitor/power_monitor_device_source.h b/base/power_monitor/power_monitor_device_source.h
index 37b065a..d29ec0a 100644
--- a/base/power_monitor/power_monitor_device_source.h
+++ b/base/power_monitor/power_monitor_device_source.h
@@ -51,6 +51,16 @@ class BASE_EXPORT PowerMonitorDeviceSource : public PowerMonitorSource {
 #endif  // OS_IOS
 #endif  // OS_MACOSX
 
+#if defined(OS_CHROMEOS)
+  // On Chrome OS, Chrome receives power-related events from powerd, the system
+  // power daemon, via D-Bus signals received on the UI thread. base can't
+  // directly depend on that code, so this class instead exposes static methods
+  // so that events can be passed in.
+  static void SetPowerSource(bool on_battery);
+  static void HandleSystemSuspending();
+  static void HandleSystemResumed();
+#endif
+
  private:
 #if defined(OS_WIN)
   // Represents a message-only window for power message handling on Windows.
diff --git a/base/power_monitor/power_monitor_device_source_chromeos.cc b/base/power_monitor/power_monitor_device_source_chromeos.cc
new file mode 100644
index 0000000..c3466ee
--- /dev/null
+++ b/base/power_monitor/power_monitor_device_source_chromeos.cc
@@ -0,0 +1,40 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/power_monitor/power_monitor.h"
+#include "base/power_monitor/power_monitor_device_source.h"
+#include "base/power_monitor/power_monitor_source.h"
+
+namespace base {
+
+namespace {
+
+// The most-recently-seen power source.
+bool g_on_battery = false;
+
+}  // namespace
+
+// static
+void PowerMonitorDeviceSource::SetPowerSource(bool on_battery) {
+  if (on_battery != g_on_battery) {
+    g_on_battery = on_battery;
+    ProcessPowerEvent(POWER_STATE_EVENT);
+  }
+}
+
+// static
+void PowerMonitorDeviceSource::HandleSystemSuspending() {
+  ProcessPowerEvent(SUSPEND_EVENT);
+}
+
+// static
+void PowerMonitorDeviceSource::HandleSystemResumed() {
+  ProcessPowerEvent(RESUME_EVENT);
+}
+
+bool PowerMonitorDeviceSource::IsOnBatteryPowerImpl() {
+  return g_on_battery;
+}
+
+}  // namespace base
diff --git a/chromeos/dbus/power_manager_client.cc b/chromeos/dbus/power_manager_client.cc
index 38d6f12..b2e8416 100644
--- a/chromeos/dbus/power_manager_client.cc
+++ b/chromeos/dbus/power_manager_client.cc
@@ -14,6 +14,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/observer_list.h"
+#include "base/power_monitor/power_monitor_device_source.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/stringprintf.h"
@@ -403,7 +404,7 @@ class PowerManagerClientImpl : public PowerManagerClient {
     dbus::MessageReader reader(signal);
     power_manager::PowerSupplyProperties protobuf;
     if (reader.PopArrayOfBytesAsProto(&protobuf)) {
-      FOR_EACH_OBSERVER(Observer, observers_, PowerChanged(protobuf));
+      HandlePowerSupplyProperties(protobuf);
     } else {
       LOG(ERROR) << "Unable to decode "
                  << power_manager::kPowerSupplyPollSignal << "signal";
@@ -420,7 +421,7 @@ class PowerManagerClientImpl : public PowerManagerClient {
     dbus::MessageReader reader(response);
     power_manager::PowerSupplyProperties protobuf;
     if (reader.PopArrayOfBytesAsProto(&protobuf)) {
-      FOR_EACH_OBSERVER(Observer, observers_, PowerChanged(protobuf));
+      HandlePowerSupplyProperties(protobuf);
     } else {
       LOG(ERROR) << "Unable to decode "
                  << power_manager::kGetPowerSupplyPropertiesMethod
@@ -444,6 +445,14 @@ class PowerManagerClientImpl : public PowerManagerClient {
     callback.Run(percent);
   }
 
+  void HandlePowerSupplyProperties(
+      const power_manager::PowerSupplyProperties& proto) {
+    FOR_EACH_OBSERVER(Observer, observers_, PowerChanged(proto));
+    const bool on_battery = proto.external_power() ==
+        power_manager::PowerSupplyProperties_ExternalPower_DISCONNECTED;
+    base::PowerMonitorDeviceSource::SetPowerSource(on_battery);
+  }
+
   void HandleRegisterSuspendDelayReply(bool dark_suspend,
                                        const std::string& method_name,
                                        dbus::Response* response) {
@@ -507,6 +516,7 @@ class PowerManagerClientImpl : public PowerManagerClient {
       FOR_EACH_OBSERVER(Observer, observers_, DarkSuspendImminent());
     else
       FOR_EACH_OBSERVER(Observer, observers_, SuspendImminent());
+    base::PowerMonitorDeviceSource::HandleSystemSuspending();
     MaybeReportSuspendReadiness();
   }
 
@@ -526,6 +536,7 @@ class PowerManagerClientImpl : public PowerManagerClient {
             << " duration=" << duration.InSeconds() << " sec";
     FOR_EACH_OBSERVER(
         PowerManagerClient::Observer, observers_, SuspendDone(duration));
+    base::PowerMonitorDeviceSource::HandleSystemResumed();
   }
 
   void IdleActionImminentReceived(dbus::Signal* signal) {